Acidic aromatization catalyst with improved activity and stability

ABSTRACT

Methods for producing supported catalysts containing a transition metal and a bound zeolite base are disclosed. These methods employ a step of impregnating the bound zeolite base with the transition metal, fluorine, and high loadings of chlorine. The resultant high chlorine content supported catalysts have improved catalyst activity in aromatization reactions.

REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 15/697,735, filed on Sep. 7, 2017, now U.S. Pat.No. 10,556,228, which claims the benefit of U.S. Provisional PatentApplication No. 62/384,746, filed on Sep. 8, 2016, the disclosures ofwhich are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present disclosure concerns methods for producing supportedcatalysts, and more particularly relates to the production of supportedaromatization catalysts containing a transition metal and a boundzeolite base using a catalyst impregnation step in which high loadingsof chlorine are present.

BACKGROUND OF THE INVENTION

The catalytic conversion of non-aromatic hydrocarbons into aromaticcompounds, often referred to as aromatization or reforming, is animportant industrial process that may be used to produce benzene,toluene, xylenes, and the like. The aromatization or reforming processoften is conducted in a reactor system that may contain one or morereactors containing transition metal based catalysts. These catalystsmay increase the selectivity to and/or the yield of the desired aromaticcompounds. These catalysts also slowly lose their activity over time,often indicated by a loss of the selectivity to desired aromaticcompounds and/or a reduction in conversion rates.

It would be beneficial to have an improved aromatization catalyst thatoffers high catalyst activity and selectivity, low fouling rates, andstability over long production runs. Accordingly, it is to these endsthat the present disclosure is principally directed.

SUMMARY OF THE INVENTION

Supported catalysts that may be used in aromatization processes aredisclosed and described herein. In one aspect, such catalysts maycomprise a bound zeolite base and, based on the total weight of thesupported catalyst, from about 0.3 wt. % to about 3 wt. % of atransition metal, from about 1.8 wt. % to about 4 wt. % of chlorine, andfrom about 0.4 wt. % to about 1.5 wt. % of fluorine. Often, thesesupported catalysts may be characterized by a peak reduction temperatureon a Temperature Programmed Reduction curve in a range from about 580°F. to about 800° F.

Methods for producing supported catalysts also are disclosed anddescribed herein. One such method for producing a supported catalyst maycomprise (a) impregnating a bound zeolite base with a transition metalprecursor, a chlorine precursor, and a fluorine precursor to form animpregnated zeolite base; and (b) drying and then calcining theimpregnated zeolite base to produce the supported catalyst. Thesupported catalyst generally comprises from about 0.3 wt. % to about 3wt. % of a transition metal, from about 1.8 wt. % to about 4 wt. % ofchlorine, and from about 0.4 wt. % to about 1.5 wt. % of fluorine, basedon the total weight of the supported catalyst. The supported catalystmay be characterized by a peak reduction temperature on a TemperatureProgrammed Reduction curve in a range from about 580° F. to about 800°F.

Supported catalysts produced by the methods provided herein may be usedin aromatization processes to produce aromatic compounds fromnon-aromatic hydrocarbons. Such catalysts may have the unexpectedcombination of increased catalyst activity and reduced fouling rates,while maintaining excellent selectivity (e.g., to benzene and toluene).

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects may bedirected to various feature combinations and sub-combinations describedin the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a plot illustrating the amounts (in wt. %) of F and Clin the supported catalysts of Example 1.

FIG. 2 presents a plot of the surface area of the supported catalysts ofExample 1 versus the amount (in wt. %) of Cl in the supported catalysts.

FIG. 3 presents a plot of the platinum dispersion of the supportedcatalysts of Example 1 versus the amount (in wt. %) of Cl in thesupported catalysts.

FIG. 4 presents a plot illustrating the amounts (in wt. %) of N and Clin the supported catalysts of Example 1.

FIG. 5 presents a plot of the molar aromatics selectivity and the molarbenzene+toluene selectivity for the supported catalysts of Example 2.

FIG. 6 presents a plot of the yield-adjusted temperature versus reactiontime for the supported catalysts of Example 3.

FIG. 7 presents a Temperature Programmed Reduction plot for thesupported catalysts of Example 4.

FIG. 8 presents a plot of the yield-adjusted temperature and hydrogenpurity versus reaction time for the supported catalysts of Example 5.

FIG. 9 presents a Temperature Programmed Reduction plot for the highchlorine supported catalyst of Example 7.

FIG. 10 presents a plot of the yield-adjusted temperature versusreaction time for the control catalyst and high chlorine supportedcatalyst of Example 7.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), may be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features may beenvisioned. For each and every aspect and each and every featuredisclosed herein, all combinations that do not detrimentally affect thedesigns, compositions, processes, or methods described herein arecontemplated with or without explicit description of the particularcombination. Additionally, unless explicitly recited otherwise, anyaspect or feature disclosed herein may be combined to describe inventivedesigns, compositions, processes, or methods consistent with the presentdisclosure.

In this disclosure, while compositions and methods are often describedin terms of “comprising” various components or steps, the compositionsand methods may also “consist essentially of” or “consist of” thevarious components or steps, unless stated otherwise.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “atransition metal” or “a chlorine precursor,” is meant to encompass one,or mixtures or combinations of more than one, transition metal orchlorine precursor, unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements may be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, transitionmetals for Group 3-12 elements, and halogens or halides for Group 17elements.

For any particular compound or group disclosed herein, any name orstructure (general or specific) presented is intended to encompass allconformational isomers, regioisomers, stereoisomers, and mixturesthereof that may arise from a particular set of substituents, unlessotherwise specified. The name or structure (general or specific) alsoencompasses all enantiomers, diastereomers, and other optical isomers(if there are any) whether in enantiomeric or racemic forms, as well asmixtures of stereoisomers, as would be recognized by a skilled artisan,unless otherwise specified. For example, a general reference to hexaneincludes n-hexane, 2-methyl-pentane, 3-methyl-pentane,2,2-dimethyl-butane, and 2,3-dimethyl-butane; and a general reference toa butyl group includes a n-butyl group, a sec-butyl group, an iso-butylgroup, and a t-butyl group.

In one aspect, a chemical “group” may be defined or described accordingto how that group is formally derived from a reference or “parent”compound, for example, by the number of hydrogen atoms removed from theparent compound to generate the group, even if that group is notliterally synthesized in such a manner. These groups may be utilized assubstituents or coordinated or bonded to metal atoms. By way of example,an “alkyl group” formally may be derived by removing one hydrogen atomfrom an alkane. The disclosure that a substituent, ligand, or otherchemical moiety may constitute a particular “group” implies that thewell-known rules of chemical structure and bonding are followed whenthat group is employed as described. When describing a group as being“derived by,” “derived from,” “formed by,” or “formed from,” such termsare used in a formal sense and are not intended to reflect any specificsynthetic methods or procedures, unless specified otherwise or thecontext requires otherwise.

Various numerical ranges are disclosed herein. When a range of any typeis disclosed or claimed herein, the intent is to disclose or claimindividually each possible number that such a range could reasonablyencompass, including end points of the range as well as any sub-rangesand combinations of sub-ranges encompassed therein, unless otherwisespecified. As a representative example, the present applicationdiscloses that the supported catalysts may contain, in certain aspects,from about 2 wt. % to about 3.8 wt. % of chlorine, based on the totalweight of the supported catalyst. By a disclosure that the chlorinecontent of the supported catalyst may be in a range from about 2 wt. %to about 3.8 wt. %, the intent is to recite that the chlorine contentmay be any amount within the range and, for example, may be equal toabout 2 wt. %, about 2.2 wt. %, about 2.4 wt. %, about 2.6 wt. %, about2.8 wt. %, about 3 wt. %, about 3.2 wt. %, about 3.4 wt. %, about 3.6wt. %, or about 3.8 wt. %. Additionally, the chlorine content may bewithin any range from about 2 wt. % to about 3.8 wt. % (for example, thechlorine content may be in a range about 2.5 wt. % to about 3.3 wt. %),and this also includes any combination of ranges between about 2 wt. %and about 3.8 wt. %. Likewise, all other ranges disclosed herein shouldbe interpreted in a manner similar to this example.

The term “about” means that amounts, sizes, formulations, parameters,and other quantities and characteristics are not and need not be exact,but may be approximate including being larger or smaller, as desired,reflecting tolerances, conversion factors, rounding off, measurementerrors, and the like, and other factors known to those of skill in theart. In general, an amount, size, formulation, parameter or otherquantity or characteristic is “about” or “approximate” whether or notexpressly stated to be such. The term “about” also encompasses amountsthat differ due to different equilibrium conditions for a compositionresulting from a particular initial mixture. Whether or not modified bythe term “about,” the claims include equivalents to the quantities. Theterm “about” may mean within 10% of the reported numerical value,preferably within 5% of the reported numerical value.

As used herein, the term “hydrocarbon” refers to a compound containingonly carbon and hydrogen atoms. Other identifiers may be utilized toindicate the presence of particular groups, if any, in the hydrocarbon(e.g., halogenated hydrocarbon indicates the presence of one or morehalogen atoms replacing an equivalent number of hydrogen atoms in thehydrocarbon).

An “aromatic” compound is a compound containing a cyclically conjugateddouble bond system that follows the Hückel (4n+2) rule and contains(4n+2) pi-electrons, where n is an integer from 1 to 5. Aromaticcompounds include “arenes” (hydrocarbon aromatic compounds, e.g.,benzene, toluene, and xylenes) and “heteroarenes” (heteroaromaticcompounds formally derived from arenes by replacement of one or moremethine (—C═) carbon atoms of the cyclically conjugated double bondsystem with a trivalent or divalent heteroatoms, in such a way as tomaintain the continuous pi-electron system characteristic of an aromaticsystem and a number of out-of-plane pi-electrons corresponding to theHückel rule (4n+2)). As disclosed herein, the term “substituted” may beused to describe an aromatic group, arene, or heteroarene, wherein anon-hydrogen moiety formally replaces a hydrogen atom in the compound,and is intended to be non-limiting, unless specified otherwise.

As used herein, the term “alkane” refers to a saturated hydrocarboncompound. Other identifiers may be utilized to indicate the presence ofparticular groups, if any, in the alkane (e.g., halogenated alkaneindicates the presence of one or more halogen atoms replacing anequivalent number of hydrogen atoms in the alkane). The term “alkylgroup” is used herein in accordance with the definition specified byIUPAC: a univalent group formed by removing a hydrogen atom from analkane. The alkane or alkyl group may be linear or branched unlessotherwise specified.

A “cycloalkane” is a saturated cyclic hydrocarbon, with or without sidechains, for example, cyclobutane, cyclopentane, cyclohexane, methylcyclopentane, and methyl cyclohexane. Other identifiers may be utilizedto indicate the presence of particular groups, if any, in thecycloalkane (e.g., halogenated cycloalkane indicates the presence of oneor more halogen atoms replacing an equivalent number of hydrogen atomsin the cycloalkane).

As used herein, the term “convertible hydrocarbon,” “convertible C₆species,” or “convertible C₇ species” refers to a hydrocarbon compoundthat is readily reacted to form aromatic hydrocarbons underaromatization process conditions. A “non-convertible hydrocarbon” is ahighly-branched hydrocarbon that is not readily reacted to form aromatichydrocarbons under aromatization process conditions. A “non-convertiblehydrocarbon” may comprise highly-branched hydrocarbons having six orseven carbon atoms with an internal quaternary carbon, or hydrocarbonshaving six carbons atoms and two adjacent internal tertiary carbons, ormixtures thereof. A “convertible C₆ species” is a hydrocarbon containingsix carbons without an internal quaternary carbon or two adjacentinternal tertiary carbons, for example, n-hexane, 2-methyl-pentane,3-methyl-pentane, cyclohexane, and methyl cyclopentane. A “convertibleC₇ species” is a hydrocarbon containing seven carbons without aninternal quaternary carbon, for example, n-heptane, 2-methyl-hexane,3-methyl-hexane, 2,3-dimethyl-pentane, 2,4-dimethyl-pentane, methylcyclohexane, and dimethyl cyclopentane. The highly branched hydrocarbonswith six or seven carbon atoms and an internal quaternary carbon maycomprise, for example, 2,2-dimethylbutane, 2,2-dimethylpentane,3,3-dimethylpentane, and 2,2,3-trimethylbutane. The highly branchedhydrocarbons with six carbon atoms and an adjacent internal tertiarycarbon may comprise, for example, 2,3-dimethylbutane. Thenon-convertible highly branched hydrocarbons do not easily convert toaromatic products and instead tend to convert to light hydrocarbonsunder aromatization process conditions.

The term “halogen” has its usual meaning. Examples of halogens includefluorine, chlorine, bromine, and iodine.

Molar selectivities are defined as:

$\begin{matrix}{{{Benzene}\mspace{14mu}{selectivity}\text{:}\mspace{14mu} S_{Bz}} = \frac{{\overset{.}{n}}_{{Bz},{prod}}}{{\overset{.}{n}}_{{{convC}\; 6},{feed}} - {\overset{.}{n}}_{{{convC}\; 6},{prod}}}} & {{Eq}.\mspace{14mu} 1} \\{{{Toluene}\mspace{14mu}{selectivity}\text{:}\mspace{14mu} S_{Tol}} = \frac{{\overset{.}{n}}_{{Tol},{prod}}}{{\overset{.}{n}}_{{{convC}\; 7},{feed}} - {\overset{.}{n}}_{{{convC}\; 7},{prod}}}} & {{Eq}.\mspace{14mu} 2} \\{{{Benzene} + {{Toluene}\mspace{14mu}{selectivity}\text{:}\mspace{14mu} S_{{Bz} + {Tol}}}} = \frac{{\overset{.}{n}}_{{Bz},{prod}} + {\overset{.}{n}}_{{Tol},{prod}}}{{\overset{.}{n}}_{{{convC}\; 6},{C\; 7},{feed}} - {\overset{.}{n}}_{{{convC}\; 6},{C\; 7},{prod}}}} & {{Eq}.\mspace{14mu} 3} \\{{{Aromatics}\mspace{14mu}{selectivity}\text{:}\mspace{14mu} S_{arom}} = \frac{{\overset{.}{n}}_{{Bz},{prod}} + {\overset{.}{n}}_{{Tol},{prod}} + {\overset{.}{n}}_{{{C\; 8} + {arom}},{prod}}}{{\overset{.}{n}}_{{{{convC}\; 6} - {C\; 8} +},{feed}} - {\overset{.}{n}}_{{{{convC}\; 6} - {C\; 8} +},{prod}}}} & {{Eq}.\mspace{14mu} 4}\end{matrix}$

Conversion is defined as the number of moles converted per mol of“convertible” hydrocarbons fed:

$\begin{matrix}{{C\; 6\mspace{14mu}{conversion}\text{:}\mspace{14mu} X_{C\; 6}} = \frac{{\overset{.}{n}}_{{{convC}\; 6},{feed}} - {\overset{.}{n}}_{{{convC}\; 6},{prod}}}{{\overset{.}{n}}_{{{convC}\; 6},{feed}}}} & {{Eq}.\mspace{14mu} 5} \\{{C\; 7\mspace{14mu}{conversion}\text{:}\mspace{14mu} X_{C\; 7}} = \frac{{\overset{.}{n}}_{{{convC}\; 7},{feed}} - {\overset{.}{n}}_{{{convC}\; 7},{prod}}}{{\overset{.}{n}}_{{{convC}\; 7},{feed}}}} & {{Eq}.\mspace{14mu} 6} \\{{{C\; 6} + {C\; 7\mspace{14mu}{conversion}\text{:}\mspace{14mu} X_{{C\; 6} + {C\; 7}}}} = \frac{{\overset{.}{n}}_{{{convC}\; 6},{feed}} + {\overset{.}{n}}_{{{convC}\; 7},{feed}} - {\overset{.}{n}}_{{{convC}\; 6},{prod}} - {\overset{.}{n}}_{{{convC}\; 7},{prod}}}{{\overset{.}{n}}_{{{convC}\; 6},{feed}} + {\overset{.}{n}}_{{{convC}\; 7},{feed}}}} & {{Eq}.\mspace{14mu} 7}\end{matrix}$

In these equations, {dot over (n)} indicates a molar flow rate in acontinuous reactor or the number of moles in a batch reactor.

Although any methods and materials similar or equivalent to thosedescribed herein may be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which may be used in connection with the presently described invention.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are supported catalysts having a high chlorine content,methods for producing such supported catalysts, and the use of thesecatalysts in aromatization or reforming processes. Beneficially, ascompared to traditional aromatization catalysts having a low chlorinecontent, the high chlorine content supported catalysts described hereinhave unexpectedly improved catalyst activity and stability, and lowerfouling rates.

While not wishing to be bound by the following theory, it is believedthat using traditional chlorine loadings that are less than that of thehigh chlorine content supported catalysts disclosed herein may result ininferior aromatization catalyst performance, while using chlorineloadings that are greater than that of the high chlorine contentsupported catalysts disclosed herein may lead to difficulties withsuccessfully impregnating the zeolite base with the desired amounts oftransition metal, chlorine, fluorine, and water. Moreover, traditionalchlorine loadings were designed, in part, to maintain the non-acidicnature of the supported catalyst, with the conventional belief thatincreasing the acidity of the catalyst would prove detrimental to bothcatalyst activity and selectivity, thus making the high chlorine contentsupported catalysts described herein, and their improved catalyticperformance, even more surprising.

Supported Catalysts

Consistent with aspects disclosed herein are supported catalystscomprising (or consisting essentially of, or consisting of) a boundzeolite base, from about 0.3 wt. % to about 3 wt. % of a transitionmetal, from about 1.8 wt. % to about 4 wt. % of chlorine, and from about0.4 wt. % to about 1.5 wt. % of fluorine. These weight percentages arebased on the total weight of the supported catalyst. The supportedcatalyst may be characterized by a peak reduction temperature on aTemperature Programmed Reduction (TPR) curve in a range from about 580°F. to about 800° F. Generally, the features of any of the catalystsdisclosed herein (e.g., the bound zeolite base, the transition metal andtransition metal content, the chlorine content, the fluorine content,and the characteristic of the TPR curve, among others) are independentlydescribed herein, and these features may be combined in any combinationto further describe the disclosed supported catalysts.

Referring first to the bound zeolite base, any suitable bound zeolitebase may be used with the high chlorine content supported catalystsdescribed herein. Typically, the bound zeolite base may comprise aninorganic oxide, examples of which may include, but are not limited to,bound medium and/or large pore zeolites (aluminosilicates), amorphousinorganic oxides, as well as mixtures thereof. Large pore zeolites oftenmay have average pore diameters in a range of from about 7 Å to about 12Å, and non-limiting examples of large pore zeolites include L-zeolite,Y-zeolite, mordenite, omega zeolite, beta zeolite, and the like. Mediumpore zeolites often may have average pore diameters in a range of fromabout 5 Å to about 7 Å. Amorphous inorganic oxides may include, but arenot limited to, aluminum oxide, silicon oxide, titania, and combinationsthereof.

The term “zeolite” generally refers to a particular group of hydrated,crystalline metal aluminosilicates. These zeolites exhibit a network ofSiO₄ and AlO₄ tetrahedra in which aluminum and silicon atoms arecrosslinked in a three-dimensional framework by sharing oxygen atoms. Inthe framework, the ratio of oxygen atoms to the total of aluminum andsilicon atoms may be equal to 2. The framework exhibits a negativeelectrovalence that typically may be balanced by the inclusion ofcations within the crystal, such as metals, alkali metals, and/orhydrogen.

In some aspects, the bound zeolite base may comprise an L-type zeolite.L-type zeolite supports are a sub-group of zeolitic supports, which maycontain mole ratios of oxides in accordance with the formula:M_(2/n)OAl₂O₃xSiO₂yH₂O. In this formula, “M” designates an exchangeablecation (one or more) such as barium, calcium, cerium, lithium,magnesium, potassium, sodium, strontium, and/or zinc, as well asnon-metallic cations like hydronium and ammonium ions, which may bereplaced by other exchangeable cations without causing a substantialalteration of the basic crystal structure of the L-type zeolite. The “n”in the formula represents the valence of “M”; “x” is 2 or greater; and“y” is the number of water molecules contained in the channels orinterconnected voids of the zeolite.

In one aspect, the bound zeolite base may comprise a bound potassiumL-type zeolite, also referred to as a K/L-zeolite, while in anotheraspect, the bound zeolite base may comprise a barium ion-exchangedL-zeolite. As used herein, the term “K/L-zeolite” refers to L-typezeolites in which the principal cation M incorporated in the zeolite ispotassium. A K/L-zeolite may be cation-exchanged (e.g., with barium) orimpregnated with a transition metal and one or more halides to produce atransition metal impregnated, halided zeolite or a K/L supportedtransition metal-halide zeolite catalyst.

In the bound zeolite base, the zeolite may be bound with a supportmatrix (or binder), and non-limiting examples of binders may include,but are not limited to, inorganic solid oxides, clays, and the like, aswell as combinations thereof. The zeolite may be bound with the binderor support matrix using any method known in the art. For instance, thebound zeolite base—comprising a zeolite and a binder—may be produced bya process comprising mixing a zeolite, such as a K/L-zeolite, with abinder, such as a silica sol, then extruding the mixture to form anextrudate, followed by drying and calcining the extrudate to form acalcined base, and then washing, drying, and calcining the calcined baseto form the bound zeolite base.

In some aspects, the binder may comprise alumina, silica, magnesia,boria, titania, zirconia, or a mixed oxide thereof (e.g., analuminosilicate), or a mixture thereof, while in other aspects, thebinder may comprise a montmorillonite, a kaolin, a cement, or acombination thereof. In a particular aspect contemplated herein, thebinder may comprise silica, alumina, or a mixed oxide thereof;alternatively, silica; alternatively, alumina; or alternatively,silica-alumina. Accordingly, the bound zeolite base may comprise asilica-bound L-zeolite, such as a silica-bound Ba/L-zeolite, asilica-bound barium ion-exchanged L-zeolite, or a silica-boundK/L-zeolite.

While not being limited thereto, bound zeolite bases (or the supportedcatalysts) encompassed herein may comprise from about 3 wt. % to about35 wt. % binder. For example, the bound zeolite base (or the supportedcatalyst) may comprise from about 5 wt. % to about 30 wt. %, or fromabout 10 wt. % to about 30 wt. % binder. These weight percentages arebased on the total weight of the bound zeolite base, or based on thetotal weight of the supported catalyst, as the context requires.

Illustrative examples of bound zeolite bases and their use in supportedcatalysts are described in U.S. Pat. Nos. 5,196,631, 6,190,539,6,406,614, 6,518,470, 6,812,180, and 7,153,801, the disclosures of whichare incorporated herein by reference in their entirety.

The supported catalyst may comprise from about 0.3 wt. % to about 3 wt.% of a transition metal. For example, the supported catalyst maycomprise from about 0.5 wt. % to about 2.5 wt. %, from about 0.5 wt. %to about 2 wt. %, or from about 0.7 wt. % to about 1.5 wt. % transitionmetal. These weight percentages are based on the total weight of thesupported catalyst.

Non-limiting examples of suitable transition metals may include iron,cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium,platinum, gold, silver, copper, and the like, or a combination of two ormore transition metals. In one aspect, the transition metal may comprisea Group 8-11 transition metal or a Group 8-10 transition metal (one ormore), while in another aspect, the transition metal may compriseplatinum (Pt). In yet another aspect, the bound zeolite base isimpregnated with only one transition metal, and the transition metal isplatinum.

In circumstances where the transition metal comprises platinum, thesupported catalyst may comprise from about 0.3 wt. % to about 3 wt. %platinum; alternatively, from about 0.5 wt. % to about 2.5 wt. %platinum; alternatively, from about 0.5 wt. % to about 2 wt. % platinum;or alternatively, from about 0.7 wt. % to about 1.5 wt. % platinum. In aparticular aspect contemplated herein, the supported catalyst maycomprise platinum on a bound K/L-zeolite.

Significantly, as compared to traditional aromatization catalysts, thesupported catalyst described herein has a relatively high loading ofchlorine (Cl), typically ranging from about 1.8 wt. % to about 4 wt. %,based on the total weight of the supported catalyst. In one aspect, thesupported catalyst may comprise from about 2 wt. % to about 3.8 wt. %chlorine. In another aspect, the supported catalyst may comprise fromabout 2.2 wt. % to about 3.6 wt. % chlorine. In yet another aspect, thesupported catalyst may comprise from about 2.2 wt. % to about 3.4 wt. %chlorine. In still another aspect, the supported catalyst may comprisefrom about 2 wt. % to about 3.3 wt. % chlorine, or from about 2.5 wt. %to about 3.3 wt. % chlorine. Unexpectedly, it was found that highloadings of chlorine in the supported catalyst may provide improvedcatalyst activity and stability, and lower fouling rates.

The supported catalyst also comprises fluorine (F), which often rangesfrom about 0.4 wt. % to about 1.5 wt. %, or from about 0.5 wt. % toabout 1.5 wt. %, based on the total weight of the supported catalyst.For instance, the supported catalyst may comprise from about 0.5 wt. %to about 1.3 wt. % fluorine, from about 0.5 wt. % to about 1.1 wt. %fluorine, or from about 0.6 wt. % to about 0.9 wt. % fluorine.

While not being limited thereto, the high chlorine content supportedcatalyst may be characterized by a weight ratio of chlorine:fluorinethat often falls within a range from about 1.5:1 to about 8:1, or fromabout 2:1 to about 6:1. In some aspects, the weight ratio ofchlorine:fluorine may range from about 2:1 to about 5:1, while in otheraspects, the weight ratio may range from about 3:1 to about 4.5:1.

Unexpectedly, the high chlorine content supported catalysts describedherein may have Temperature Programmed Reduction (TPR) curves that aredistinctly different from traditional low chlorine content supportedcatalysts (i.e., having from 0.3 wt. % to 1.5 wt. % Cl). In one aspect,for instance, the high chlorine content supported catalysts disclosedherein may be characterized by a peak temperature on a TPR curve in arange from about 580° F. to about 800° F. In another aspect, the peaktemperature on the TPR curve may fall within a range from about 580° F.to about 750° F., from about 600° F. to about 730° F., from about 600°F. to about 720° F., or from about 630° F. to about 690° F. The peaktemperature on the TPR curve is the temperature of the highest peak onthe TPR curve. As shown in the examples that follow, the peaktemperatures for traditional low chlorine content supported catalystsare much lower.

A “traditional low chlorine content supported catalyst” generallyencompasses aromatization catalysts, as described herein, that containany amount of Cl in the range from 0.3 wt. % to 1.5 wt. % Cl, based onthe total weight of the supported catalyst. Thus, a traditional lowchlorine content supported catalyst may include a supported catalysthaving any Cl content within the 0.3 wt. % to 1.5 wt. % range, such asfrom 0.3 wt. % to 1.2 wt. % Cl, or from 0.5 wt. % to 1.1 wt. % Cl.Additionally, the traditional low chlorine content supported catalystmay have a Cl content of about 0.4 wt. %, about 0.5 wt. %, about 0.6 wt.%, about 0.7 wt. %, about 0.8 wt. %, about 0.9 wt. %, about 1 wt. %,about 1.1 wt. %, about 1.2 wt. %, about 1.3 wt. %, or about 1.4 wt. %.

In another aspect, for instance, the high chlorine content supportedcatalysts disclosed herein may be characterized by a peak temperature ona TPR curve that is at least 100° F. higher than the peak TPRtemperature for a traditional low chlorine content supported catalyst.In another aspect, the peak temperature on the TPR curve may be at leastabout 150° F. higher, at least about 200° F. higher, from about 100° F.to about 400° F. higher, from about 120° F. to about 300° F. higher, orfrom about 100° F. to about 250° F. higher.

In addition, the high chlorine content supported catalysts disclosedherein may be characterized by a TPR curve having a lower temperaturepeak and a higher temperature peak (i.e., two peaks), and the highertemperature peak is greater in height than the lower temperature peak.As shown in the examples that follow, the opposite is true for lowchlorine content supported catalysts—i.e., the lower temperature peak isgreater in height than the higher temperature peak.

Moreover, the high chlorine content supported catalysts disclosed hereinmay have a total nitrogen (N) content that is greater than that of lowchlorine content supported catalysts (i.e., having from 0.3 wt. % to 1.5wt. % Cl), when compared under the same catalyst preparation conditions.In some instances, the total nitrogen content of the high chlorinecontent supported catalyst may be at least about 50% greater, at leastabout 100% greater, or at least about 200% greater, and often up to500-1000% greater, than that of the low chlorine content supportedcatalyst.

In some aspects, the supported catalyst comprises nitrogen (N), whichoften ranges from about 0.4 wt. % to about 1.6 wt. %, based on the totalweight of the supported catalyst. For instance, the supported catalystmay comprise from about 0.5 wt. % to about 1.4 wt. % nitrogen, fromabout 0.6 wt. % to about 1.3 wt. % nitrogen, or from about 0.7 wt. % toabout 1.2 wt. % nitrogen.

Furthermore, the performance of the high chlorine content supportedcatalysts disclosed herein in aromatization reactions is improved.Surprisingly, these supported catalysts have higher catalyst activityand stability, as quantified by the T_(SOR) (start of run temperature),T_(EOR) (end of run temperature), and FR (fouling rate) metricsdiscussed in greater detail in the examples that follow. Generally, thehigh chlorine content supported catalysts described herein may have alower T_(SOR), a lower T_(EOR), and/or a lower FR than that of a lowchlorine content supported catalyst (i.e., having from 0.3 wt. % to 1.5wt. % chlorine), when compared under the same catalyst preparation andaromatization reaction conditions. Thus, the comparison is for supportedcatalysts having the same platinum, fluorine, and other compositionalattributes (with the exception of chlorine content), and prepared in thesame manner, and tested under the same aromatization reaction conditions(see Example 3 below).

The high chlorine content supported catalysts may be characterized by aT_(SOR) (start of run temperature), as described herein, which often mayfall within a range from about 915° F. to about 935° F., or from about915° F. to about 930° F. Additionally or alternatively, these supportedcatalysts may be characterized by a T_(EOR) (end of run temperature), asdescribed herein, which often may fall within a range from about 920° F.to about 940° F., or from about 920° F. to about 930° F. Additionally oralternatively, these supported catalysts may be characterized by a FR(fouling rate), as described herein, which often may be less than about0.12° F./min, or less than about 0.1° F./min.

In contrast to these improvements, and unexpectedly, the high chlorinecontent supported catalysts may have surface areas and platinumdispersions that are comparable to those of low chlorine contentsupported catalysts (i.e., having from 0.3 wt. % to 1.5 wt. % chlorine),when compared under the same catalyst preparation conditions. Forinstance, the high chlorine content supported catalysts may have surfaceareas and platinum dispersions that are substantially the same as thoseof low chlorine content supported catalysts, when compared under thesame catalyst preparation conditions. In these circumstances,“substantially” the same means within +/−20%, and more typically, within+/−15%, or within +/−10%.

In addition, the high chlorine content supported catalysts may becharacterized by an aromatics selectivity (or a benzene+tolueneselectivity) that is substantially the same as that of a low chlorinecontent supported catalyst (having from 0.3 wt. % to 1.5 wt. %chlorine), when compared under the same catalyst preparation andaromatization reaction conditions. In these circumstances,“substantially” the same means within +/−10%, and more typically, within+/−6%, or within +/−4%.

Methods for Producing Supported Catalysts

Various methods for producing supported catalysts, such as supportedaromatization catalysts, are disclosed and described. One such methodfor producing a supported catalyst may comprise (or consist essentiallyof, or consist of) (a) impregnating a bound zeolite base with atransition metal precursor, a chlorine precursor, and a fluorineprecursor to form an impregnated zeolite base; and (b) drying and thencalcining the impregnated zeolite base to produce the supportedcatalyst. The supported catalyst may comprise, based on the total weightof the supported catalyst, from about 0.3 wt. % to about 3 wt. % of atransition metal, from about 1.8 wt. % to about 4 wt. % of chlorine, andfrom about 0.4 wt. % to about 1.5 wt. % of fluorine. Further, thesupported catalyst may be characterized by a peak reduction temperatureon a Temperature Programmed Reduction (TPR) curve in a range from about580° F. to about 800° F.

Generally, the features of any of the methods disclosed herein (e.g.,the bound zeolite base, the transition metal precursor, the transitionmetal and transition metal content, the chlorine precursor, the chlorinecontent, the fluorine precursor, the fluorine content, thecharacteristics of the TPR curve, the conditions under which theimpregnation step is conducted, the conditions under which the dryingand calcining are conducted, among others) are independently describedherein, and these features may be combined in any combination to furtherdescribe the disclosed supported methods. Moreover, other process stepsmay be conducted before, during, and/or after any of the steps listed inthe disclosed methods, unless stated otherwise. Additionally, supportedcatalysts (such as supported aromatization catalysts) produced inaccordance with any of the disclosed methods/processes are within thescope of this disclosure and are encompassed herein.

Referring now to step (a) of the method for producing a supportedcatalyst (often referred to as the impregnation step), the bound zeolitebase may be impregnated with a transition metal precursor, a chlorineprecursor, and a fluorine precursor to form an impregnated zeolite base.The bound zeolite base in step (a) may be produced by any techniqueknown to those skilled in the art. For instance, the bound zeolitebase—comprising a zeolite and a binder—may be produced by a processcomprising mixing or combining a zeolite with a binder to form amixture, then extruding the mixture to form an extrudate, followed bydrying and calcining the extrudate to form a calcined base, and thenwashing, drying, and calcining the calcined base to form the boundzeolite base.

The transition metal precursor, chlorine precursor, and fluorineprecursor in the impregnation step encompass any compounds that maydeposit the transition metal, chlorine, and/or fluorine in or on thebound zeolite base, thereby forming the impregnated zeolite base. Thisdescription is meant to encompass (1) compounds that serve as precursorfor only one material—for example, ammonium chloride may be a chlorineprecursor for chlorine—and (2) compounds that serve as precursor formore than one material—for example, platinum(II) chloride may be both atransition metal precursor and a chlorine precursor for platinum andchlorine, while a chlorofluorocarbon compound may be both a chlorineprecursor and a fluorine precursor for chlorine and fluorine.

Illustrative and non-limiting examples of transition metal precursorsthat are suitable for use in impregnating the bound zeolite base withplatinum include, but are not limited to, tetraamineplatinum(II)chloride, tetraamineplatinum(II) nitrate, platinum(II) acetyl acetonate,platinum(II) chloride, ammonium tetrachloroplatinate(II), chloroplatinicacid, platinum (II) nitrate, and the like, as well as mixtures orcombinations thereof. Illustrative and non-limiting examples of chlorineprecursors include hydrochloric acid, carbon tetrachloride,tetrachloroethylene, chlorobenzene, methyl chloride, methylene chloride,chloroform, allyl chloride, trichloroethylene, a chloramine, a chlorineoxide, a chlorine acid, chlorine dioxide, dichlorine monoxide,dichlorine heptoxide, chloric acid, perchloric acid, ammonium chloride,tetramethylammonium chloride, tetraethylammonium chloride,tetrapropylammonium chloride, tetrabutylammonium chloride,methyltriethylammonium chloride, and the like, as well as combinationsthereof. Illustrative and non-limiting examples of fluorine precursorsinclude hydrofluoric acid, 2,2,2-trifluoroethanol, tetrafluoroethylene,carbon tetrafluoride, carbon trifluoride, fluoromethane,heptafluoropropane, decafluorobutane, hexafluoroisopropanol,tetrafluoropropanol, pentafluoropropanol, hexafluorophenylpropanol,perfluorobutyl alcohol, hexafluor-2-propanol, pentafluoro-1-propanol,tetrafluoro-1-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol,2,2,3,3,3-pentafluoro-1-propanol, ammonium fluoride, tetramethylammoniumfluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride,tetrabutylammonium fluoride, methyltriethylammonium fluoride, and thelike, as well as combinations thereof.

Any suitable method or technique known to those of skill in the art thatresults in adequate dispersion of the transition metal on the supportedcatalyst may be used in the impregnation step. One such method involvesmixing the bound zeolite base with any suitable transition metalprecursor, where the transition metal precursor may be present in asolution of any suitable solvent, such as water. Likewise, for thehalogens, the impregnation step may comprise mixing the bound zeolitebase with any suitable chlorine precursor and/or fluorine precursor, andin any order or sequence. For instance, the bound zeolite base may bemixed with a solution of the chlorine precursor, a solution of thefluorine precursor, or a solution of both the chlorine precursor and thefluorine precursor in a suitable solvent. In one aspect, the boundzeolite base may be mixed with a combination of the transition metalprecursor, the chlorine precursor, and the fluorine precursor (i.e., alltogether), such as may be accomplished by mixing the bound zeolite basewith an aqueous solution comprising the transition metal precursor, thechlorine precursor, and the fluorine precursor. An incipient wetnesstechnique may be used. In another aspect, the combining of thetransition metal precursor, the chlorine precursor, and the fluorineprecursor with the bound zeolite base may be done sequentially, or inany order or combination.

Yet, in other aspects, the bound zeolite base may be impregnated withchlorine and/or fluorine in the vapor phase. For instance, the boundzeolite base may be contacted with a stream comprising a chlorineprecursor and/or a fluorine precursor. Suitable chlorine precursors andfluorine precursors may include those listed hereinabove, as well aschlorine gas (Cl₂) and fluorine gas (F₂).

Referring now to step (b), the impregnated zeolite base may be dried andthen calcined to produce the supported catalyst. Any suitabletemperatures, pressures, time periods, and atmospheres may be used inthe drying and calcining steps.

In one aspect, the drying step may comprise contacting the impregnatedzeolite base with a drying gas stream comprising (or consistingessentially, or consisting of) an inert gas (e.g., nitrogen), oxygen,air, or any mixture or combination thereof; alternatively, nitrogen;alternatively, helium; alternatively, neon; alternatively, argon;alternatively, oxygen; or alternatively, air. While not being limitedthereto, the drying step generally may be conducted at a dryingtemperature in a range from about 50° C. to about 200° C.;alternatively, from about 100° C. to about 200° C.; alternatively, fromabout 85° C. to about 175° C.; or alternatively, from about 80° C. toabout 150° C. In these and other aspects, these temperature ranges alsoare meant to encompass circumstances where the drying step is conductedat a series of different temperatures, instead of at a single fixedtemperature, falling within the respective ranges. In some aspects, thedrying step may be performed at atmospheric pressure, or at any suitablesub-atmospheric pressure, such as less than about 150 Torr, less thanabout 125 Torr, less than about 100 Torr, or less than about 50 Torr.

The duration of the drying step is not limited to any particular periodof time. Typically, the drying step may be conducted in a time periodranging from as little as 30 minutes to as long as 8 hours (or more),but more typically, the drying step may be conducted in a time periodthat may be in a range from about 1 hour to about 8 hours, such as, forexample, from about 1 hour to about 7 hours, from about 1 hour to about6 hours, from about 2 hours to about 7 hours, or from about 2 hours toabout 6 hours.

The calcining step may be conducted at a variety of temperatures andtime periods. Typical peak calcining temperatures often fall within arange from about 200° C. to about 600° C., such as from about 215° C. toabout 500° C., from about 230° C. to about 450° C., or from about 230°C. to about 350° C. In these and other aspects, these temperature rangesalso are meant to encompass circumstances where the calcination step isconducted at a series of different temperatures (e.g., an initialcalcination temperature, a peak calcination temperature), instead of ata single fixed temperature, falling within the respective ranges. Forinstance, the calcination step may start at an initial temperature whichis the same as the drying temperature in the drying step. Subsequently,the temperature of the calcination may be increased over time to a peakcalcining temperature, for example, in a range from about 230° C. toabout 350° C.

The duration of the calcining step is not limited to any particularperiod of time. Hence, the calcining step may be conducted, for example,in a time period ranging from as little as 30-45 minutes to as long as10-12 hours, or more. The appropriate calcining time may depend upon,for example, the initial/peak calcining temperature and the conditionsof the drying step, among other variables. Generally, however, thecalcining step may be conducted in a time period that may be in a rangefrom about 45 minutes to about 12 hours, such as, for example, fromabout 1 hour to about 12 hours, from about 1 hour to about 10 hours,from about 1 hour to about 5 hours, or from about 1 hour to about 3hours.

The calcining step may be conducted in a calcining gas stream thatcomprises (or consists essentially of, or consists of) an inert gas(e.g., nitrogen), oxygen, air, or any mixture or combination thereof. Insome aspects, the calcining gas stream may comprise air, while in otheraspects, the calcining gas stream may comprise a mixture of air andnitrogen. Yet, in certain aspects, the calcining gas stream may be aninert gas, such as nitrogen and/or argon.

The methods for preparing a supported catalyst disclosed herein mayfurther comprise a reducing step after step (b), i.e., after drying andcalcining the impregnated zeolite base to produce the supportedcatalyst. This reducing step may comprise contacting the supportedcatalyst with a reducing gas stream comprising hydrogen to produce areduced (or activated) supported catalyst. Often, the reducing gasstream comprises molecular hydrogen, either alone or with an inert gas,such as helium, neon, argon, nitrogen, and the like, and this includescombinations of two or more of these inert gasses. In certain aspects,the reducing gas stream may comprise (or consist essentially of, orconsist of) molecular hydrogen and nitrogen. Moreover, molecularhydrogen may be the major component of the reducing gas stream (greaterthan 50 mol %), while in other aspects, molecular hydrogen may be aminor component (between 5-35 mol %, or between 1-6 mol %). In anotheraspect, the reducing gas stream may comprise (or consist essentially of,or consist of) molecular hydrogen and hydrocarbons.

The reducing step may be conducted at a variety of temperatures and timeperiods. For instance, the reducing step may be conducted at a reducingtemperature in a range from about 100° C. to about 700° C.;alternatively, from about 200° C. to about 600° C.; alternatively, fromabout 200° C. to about 575° C.; alternatively, from about 350° C. toabout 575° C.; alternatively, from about 400° C. to about 550° C.; oralternatively, from about 450° C. to about 550° C. In these and otheraspects, these temperature ranges also are meant to encompasscircumstances where the reducing step is conducted at a series ofdifferent temperatures, instead of at a single fixed temperature,falling within the respective ranges.

The duration of the reducing step is not limited to any particularperiod of time. Hence, the reducing step may be conducted, for example,in a time period ranging from as little as 1 hour to as long as 48-72hours, or more. For example, the reducing step may be conducted in atime period that may be in a range from about 1 hour to about 48 hours,from about 3 hours to about 36 hours, from about 5 hours to about 36hours, from about 2 hours to about 30 hours, or from about 10 hours toabout 30 hours.

In one aspect, the reducing step may be performed ex-situ. In thisaspect, the high chlorine content supported catalyst is converted to areduced (or activated) supported catalyst according to the proceduresdescribed above. This reduction may occur at the catalyst manufacturingsite or another site. The reduced (or activated) supported catalyst maythen be packaged under air or under an inert gas and is then storedprior to being loaded into the aromatization reactor and used in thearomatization reactor system. Prior to use, a reduction step may beperformed to reduce any supported catalyst that became oxidized afterthe first reduction, for example during storage, transport and loading.This second reduction may require the same or less time than the in-situreduction described below.

In another aspect, the reducing step may be performed in-situ. In thisaspect, the high chlorine content supported catalyst is packaged afterthe calcining step. The high chlorine content supported catalyst may bestored for an extended period of time prior to loading into thearomatization reactor. After loading, the high chlorine contentsupported catalyst is then converted to a reduced (or activated)supported catalyst according to the procedures described above.

Unexpectedly, despite the high chlorine content of the supportedcatalysts disclosed herein, the reduced (or activated) supportedcatalyst may have significantly less chlorine present after the reducingstep. For instance, the reduced (or activated) supported catalyst maycomprise from about 0.2 wt. % to about 1.3 wt. % chlorine, from about0.2 wt. % to about 0.8 wt. % chlorine, or from about 0.3 wt. % to about1 wt. % chlorine. These weight percentages are based on the total weightof the reduced (or activated) supported catalyst.

Reforming Processes with Aromatization Catalysts

Also encompassed herein are various processes for reforminghydrocarbons. One such reforming process may comprise (or consistessentially of, or consist of) contacting a hydrocarbon feed with asupported aromatization catalyst under reforming conditions in a reactorsystem to produce an aromatic product. The supported aromatizationcatalyst used in the reforming process may be any supported catalystdisclosed herein (i.e., any high chlorine content supported catalystdisclosed herein) and/or may be produced by any method for producing asupported catalyst disclosed herein.

The reactor systems for reforming and the respective reformingconditions are well known to those of skill in the art and aredescribed, for example, in U.S. Pat. Nos. 4,456,527, 5,389,235,5,401,386, 5,401,365, 6,207,042, and 7,932,425, the disclosures of whichare incorporated herein by reference in their entirety.

Likewise, typical hydrocarbon feeds are disclosed in these references.Often, the hydrocarbon feed may be a naphtha stream or light naphthastream. In certain aspects, the hydrocarbon feed may comprisenon-aromatic hydrocarbons, for example, the hydrocarbon feed maycomprise C₆-C₉ alkanes and/or cycloalkanes, or C₆-C₈ alkanes and/orcycloalkanes (e.g., hexane, heptane, cyclohexane), and the like.

As described herein, and unexpectedly, the high chlorine contentsupported catalysts herein may have improved catalyst activity andstability, and reduced fouling rates in aromatization or reformingreactions, as compared to low chlorine content supported catalysts(i.e., having from 0.3 wt. % to 1.5 wt. % Cl).

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, modifications, and equivalentsthereof which, after reading the description herein, may suggestthemselves to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

Weight percentages of Pt, Cl, F, and N were determined using X-rayfluorescence (XRF), and are based on the total weight of the supportedcatalyst, unless stated otherwise. Surface areas were determined usingthe BET method, and platinum dispersions were determined by COChemisorption.

Supported catalysts were tested for their performance in aromatizationreactions using the following general procedure, unless noted otherwise.The supported aromatization catalysts were ground and sieved to about25-45 mesh (US), and 1 cc of the sieved supported catalyst was placed ina ⅜-inch OD stainless steel reactor vessel in a temperature controlledfurnace. After reducing the supported catalyst under flowing molecularhydrogen, a feed stream of aliphatic hydrocarbons and molecular hydrogenwas introduced to the reactor vessel at a pressure of 100 psig, ahydrogen:hydrocarbon molar ratio of 1.3:1, and a liquid hourly spacevelocity (LHSV) of 12 hr⁻¹. The aliphatic hydrocarbon feed containedapproximately 0.61 mole fraction of convertible C₆ species and 0.21 molefraction of convertible C₇ species. The balance was aromatics, C₈+, andnon-convertible hydrocarbon. The reactor temperature was then adjustedto maintain a target conversion of 63 wt. % aromatics in the C₅ ⁺fraction of the reactor effluent as determined gas chromatography. Theamounts of the numerous feedstock components and product components,including benzene and toluene present, also were recorded forselectivity calculations.

The temperature at the start of run (T_(SOR)) and the fouling rate(abbreviated FR, units of ° F./hr.) of a supported catalyst sample wasdetermined by plotting the temperature (yield-adjusted catalysttemperature) required to maintain a total yield of aromatics (such asbenzene and toluene) at 63 wt. % over time at the standard testconditions provided above. As used herein, the term “yield-adjustedtemperature” refers to the catalyst bed temperature in a lab-scalereactor system which has been adjusted to account for samples taken whenthe reactor effluent does not contain 63 wt. % aromatics in the C₅ ⁻fraction of the reactor effluent. The adjustment factor (for example, inunits of ° F./wt. %) was determined by prior experiments with similarcatalysts. A linear regression analysis of the temperatures collectedbetween 15 and 40 hours results in the formula, T_(adj)=FR*t+T_(SOR),where T_(adj) is the yield-adjusted temperature, FR is the fouling rate,t is time, and T_(SOR) is the Start of Run temperature (temperatureneeded to achieve 63 wt. % aromatics yield at a hypothetical time zero).The total time on stream was 40 hours, and the End of Run temperature(abbreviated T_(EOR)) at 40 hours also was determined; T_(EOR) is thetemperature needed to achieve 63 wt. % aromatics yield at the end of the40-hour run. Initial low conversion and catalyst break-in conditionswere the primary reasons that the temperatures prior to 15 hours werenot included in the determination of T_(SOR) and FR.

Temperature-programmed reduction (TPR) is a method of examining thereducibility of catalytically active materials, in these examples withhydrogen, as a function of the temperature. For the TPR test, thecalcined catalyst was ground and sieved to 25-45 mesh (US) and placed ina sample vessel, which can be, for example, a simple U-tube. This samplevessel was then positioned in an oven equipped with temperatureregulation and a thermocouple to record the temperature of the catalystbed. The sample vessel was first purged with an inert gas (for example,argon or nitrogen). After a few minutes, 10% by volume of hydrogen wasintroduced into the inert gas stream by means of a flow regulator at atotal gas flow rate of 50 cc/min. The sample vessel was flushed with themeasurement gas at room temperature before commencement of themeasurement. The sample vessel was then heated in the oven at a rate of10° C./min. The effluent from the sample vessel was passed to a thermalconductivity detector for determination of hydrogen uptake as a functionof temperature.

Example 1

A standard bound KL-zeolite base consisting of approximately 17 wt. %silica binder was used as the starting material for Example 1. The boundzeolite base was impregnated with Pt, Cl, and F via incipient wetnesstechniques by contacting the bound zeolite base with an aqueous solutioncontaining platinum tetraammonium chloride (Pt(NH₃)₄Cl₂.xH₂O), ammoniumchloride, and ammonium fluoride. Then, the impregnated base was dried at95° C., and calcined at 900° F. to form the supported aromatizationcatalysts.

In Example 1, supported catalysts containing approximately 1 wt. % Pt,0.6 wt. % F, and a range of Cl contents were produced. FIG. 1illustrates the F and Cl contents of these supported catalysts, with theamount of Cl ranging from less than 1 wt. % to over 3 wt. %. Despitethis large range of Cl contents, the surface areas of the supportedcatalysts were substantially constant, as shown in FIG. 2, and theplatinum dispersions in the supported catalysts were substantiallyconstant, as shown in FIG. 3. In contrast, FIG. 4 demonstrates that theN content of the supported catalyst increased linearly with the Clcontent of the supported catalyst.

Example 2

In Example 2, supported catalysts were produced as described in Example1, and the range of Cl contents was from 0.7 wt. % to 3.1 wt. %. Thesesupported catalysts were compared to two standard supported catalysts: aLarge-Scale Control (having 0.98 wt. % Pt, 0.85 wt. % Cl, and 0.71 wt. %F) and a Laboratory Control (having 1.01 wt. % Pt, 0.87 wt. % Cl, and0.61 wt. % F). The Large-Scale Control and Laboratory Control are nearlyidentical supported catalysts, with the Large-Scale Control being ahistorical control catalyst produced on large-scale equipment typical ofa catalyst manufacturer, and the Laboratory Control being a controlcatalyst made in the laboratory at the same time and using the sameequipment as the experimental catalysts.

Using the 40-hour test procedure described above, the selectivity toaromatics and selectivity for benzene+toluene were determined for eachsupported catalyst. FIG. 5 compares the average aromatics selectivityand the average benzene+toluene selectivity for these supportedcatalysts. As shown in FIG. 5, the selectivity performance of thesupported catalysts with 0.7 wt. % to 3.1 wt. % Cl was comparable to thestandard catalysts, and the amount of Cl (high versus low) did notsignificantly impact the selectivity performance of the supportedcatalysts.

Example 3

In Example 3, supported catalysts were produced as described in Example1, and the Cl contents were 0.75 wt. %, 1.1 wt. %, 2.2 wt. %, 2.7 wt. %,and 3.1 wt. %. These supported catalysts were compared to the twostandard aromatization catalysts: the Large-Scale Control and theLaboratory Control.

FIG. 6 compares the yield-adjusted temperature versus the reaction timefor each supported catalyst, using the 40-hour test procedure describedabove. Table I summarizes the relevant catalyst performance metrics fromFIG. 6. As shown in the table and figure, the high chlorine contentsupported catalysts (2.2 to 3.1 wt. %), unexpectedly, had the bestperformance of all of the catalysts: the highest catalyst activities(lowest T_(SOR) and T_(EOR)) and the lowest fouling rates.Interestingly, these beneficial results were achieved withoutsignificant changes in catalyst surface area, platinum dispersion, orcatalyst selectivity (see Example 1 and Example 2).

TABLE I Example 3 — Catalyst performance summary. Fouling T_(SOR)T_(EOR) Rate Chlorine (wt. %) (° F.) (° F.) (° F./hr.) 0.85 936 941 0.14Large-Scale Control 0.87 936 941 0.12 Experimental Control 0.75 946 9500.05 1.1 929 934 0.13 2.2 922 925 0.05 2.7 923 926 0.08 3.1 920 925 0.10

Example 4

In Example 4, supported catalysts were produced as described in Example1, and the Cl contents were 1.1 wt. %, 2.2 wt. %, 2.7 wt. %, and 3.1 wt.%. FIG. 7 is a Temperature Programmed Reduction (TPR) plot for thesupported catalysts containing ˜0.9 wt. % Cl (Large-Scale Control), 1.1wt. % Cl, 2.2 wt. % Cl, 2.7 wt. % Cl, and 3.1 wt. % Cl.

From a comparison of the high chlorine content supported catalysts(2.2-3.1 wt. %) with the low chlorine content supported catalysts(0.9-1.1 wt. %), a few general trends are observed. First, the peaktemperatures (the temperature of the highest peak on the curve) aresignificantly higher for the high chlorine content supported catalystsas compared to the low chlorine content supported catalysts. Second, asto the relative heights of the peaks, the higher temperature peak forthe high chlorine content supported catalysts is larger than the lowertemperature peak, while for the low chlorine content supportedcatalysts, the opposite is true. Table II summarizes the respective peaktemperature and temperature of the second largest peak from the plots inFIG. 7.

TABLE II Example 4 — TPR summary. TPR Peak Second Largest TemperatureTPR Peak Chlorine (wt. %) (° F.) Temperature (° F.) 0.85 464 614Large-Scale Control 1.1 518 636 2.2 658 500 2.7 670 497 3.1 670 492

Example 5

In Example 5, a supported catalyst was produced as described in Example1, and the Cl content was 2.7 wt. %. This catalyst was evaluated againstthe Large-Scale Control catalyst (0.85 wt. % Cl), for long-term activityand stability performance, and catalyst fouling rate. For this 2500-hrtest, 80 cc of the supported catalyst was reduced in 10 mol % hydrogenin nitrogen, then a feed stream of aliphatic hydrocarbons and molecularhydrogen was introduced to a 1″ reactor containing the catalyst at apressure of 65 psig, a hydrogen:hydrocarbon ratio of 2:1, and a LHSV=1.6hr⁻¹ to obtain catalyst performance data over time. The total yield ofaromatics was maintained at 83.5 wt. % over the 2500 hr run by adjustingthe temperature to maintain the desired yield, as described above.

FIG. 8 compares the yield-adjusted temperature versus the reaction timefor each catalyst. As shown in the figure, the high chlorine contentsupported catalyst (2.7 wt. %), unexpectedly, had superior performance:higher catalyst activities throughout the 2500-hr run (lower T_(SOR) andT_(EOR)) and a lower fouling rate, indicative of a higher stabilitycatalyst.

Example 6

In Example 6, a supported catalyst was produced as described in Example1, and the Cl content was 2.7 wt. %. This catalyst was evaluated againstthe Large-Scale Control catalyst. These catalysts were subjected to acontrolled reduction step at 950° F. for 1 hour with 100% H₂ todetermine the amount of Cl that remains after the reduction step. TableIII summarizes the results. While the F content is relatively unchanged,the Cl content and N content, surprisingly, are reduced significantlyfrom the respective amounts present in the supported aromatizationcatalyst, prior to a reduction (or activation) step.

TABLE III Example 6 — Catalyst property summary. F Cl Cl N Catalyst (wt.%) (wt. %) (% loss) (wt. %) Large-Scale Control 0.54 0.34 62 0.01 HighCl 0.53 0.40 85 0.01

Example 7

In Example 7, a supported catalyst was produced as described in Example1, and the Pt content was ˜1 wt. % and the Cl content was 2.5 wt. %.Table IV summarizes the catalyst properties of the high chlorine contentcatalyst and that of the Large-Scale Control catalyst. The platinumcontent, platinum dispersion, surface area, and F content of thesecatalysts were substantially the same, while the Cl and N contents weresignificantly higher for the high chlorine content catalyst (2.5 wt. %Cl). FIG. 9 is a Temperature Programmed Reduction (TPR) plot for thesupported catalyst containing 2.5 wt. % Cl. The peak temperature wasapproximately 668° F., and the temperature of the second largest peakwas approximately 490° F. These temperatures are consistent with thehigh chlorine content catalysts evaluated in Example 4 (see Table II andFIG. 7).

FIG. 10 compares the yield-adjusted temperature versus the reaction timefor the Large-Scale Control catalyst and the high chlorine contentcatalyst (2.5 wt. % Cl). The 40-hour test procedure in Example 3 wasused, with the exception that the total yield of aromatics (such asbenzene and toluene) was maintained at 66 wt. % over time at thestandard test conditions. Table V summarizes the relevant catalystperformance metrics from FIG. 10. As shown in the table and figure, thehigh chlorine content supported catalyst (2.5 wt. %), unexpectedly, hadfar superior performance to that of the control catalyst: highercatalyst activity (lower T_(SOR) and T_(EOR)) and a lower fouling rate.Interestingly, these beneficial results were achieved withoutsignificant changes in the platinum content, platinum dispersion,surface area, and F content of the catalyst.

TABLE IV Example 7 — Catalyst property summary. Surface Platinum F NArea Dispersion Chlorine (wt. %) (wt. %) (wt. %) (m²/g) (%) 0.85 0.710.3 177 67 Large-Scale Control 2.5 0.70 1.0 170 67

TABLE V Example 7 — Catalyst performance summary. T_(SOR) T_(EOR)Fouling Rate Chlorine (wt. %) (° F.) (° F.) (° F./hr.) 0.85 938 944 0.14Large-Scale Control 2.5 923 926 0.08

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention may include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, may “consist essentially of” or “consist of”):

Aspect 1. A method of producing a supported catalyst, the methodcomprising:

(a) impregnating a bound zeolite base with a transition metal precursor,a chlorine precursor, and a fluorine precursor to form an impregnatedzeolite base; and

(b) drying and then calcining the impregnated zeolite base to producethe supported catalyst; wherein the supported catalyst comprises, basedon the total weight of the supported catalyst:

from about 0.3 wt. % to about 3 wt. % of a transition metal;

from about 1.8 wt. % to about 4 wt. % of chlorine; and

from about 0.4 wt. % to about 1.5 wt. % of fluorine; and

wherein the supported catalyst is characterized by a peak reductiontemperature on a Temperature Programmed Reduction curve in a range fromabout 580° F. to about 800° F.

Aspect 2. The method defined in aspect 1, wherein the bound zeolite baseis produced by a process comprising:

combining a zeolite with a binder to form a mixture, and extruding themixture to form an extrudate;

drying and calcining the extrudate to form a calcined base; and

washing, drying, and calcining the calcined base to form the boundzeolite base.

Aspect 3. The method defined in aspect 1 or 2, wherein drying and thencalcining the impregnated zeolite base comprises any suitable dryingconditions or any drying conditions disclosed herein, e.g., a dryingtemperature in a range from about 50° C. to about 200° C., or from about80° C. to about 150° C., and drying at atmospheric pressure orsub-atmospheric pressure, e.g., less than about 150 Torr, or less thanabout 50 Torr.

Aspect 4. The method defined in any one of the preceding aspects,wherein drying and then calcining the impregnated zeolite base comprisesany suitable calcining conditions or any calcining conditions disclosedherein, e.g., a peak calcining temperature in a range from about 200° C.to about 500° C., or from about 230° C. to about 350° C., and in acalcining gas stream comprising nitrogen, oxygen, air, or anycombination thereof.

Aspect 5. The method defined in any one of the preceding aspects,wherein the method further comprises a reducing step after the dryingand calcining of the impregnated zeolite base, the reducing stepcomprising contacting the supported catalyst with any suitable reducinggas stream or any reducing gas stream disclosed herein (e.g., comprisinghydrogen) to produce a reduced (or activated) supported catalyst.

Aspect 6. The method defined in aspect 5, wherein the reducing step isconducted at any suitable reducing temperature or any reducingtemperature disclosed herein, e.g., in a range from about 100° C. toabout 700° C., or from about 200° C. to about 600° C.

Aspect 7. The method defined in any one of the preceding aspects,wherein impregnating the bound zeolite base with the transition metalprecursor comprises mixing the bound zeolite base with any suitabletransition metal precursor or any transition metal precursor disclosedherein, e.g., tetraamineplatinum(II) chloride, tetraamineplatinum(II)nitrate, platinum(II) acetyl acetonate, platinum(II) chloride, ammoniumtetrachloroplatinate(II), chloroplatinic acid, platinum (II) nitrate, ora combination thereof.

Aspect 8. The method defined in any one of the preceding aspects,wherein impregnating the bound zeolite base with the chlorine precursorand the fluorine precursor comprises mixing the bound zeolite base withany suitable chlorine precursor and/or fluorine precursor, or anychlorine precursor and/or fluorine precursor disclosed herein, e.g.,ammonium chloride, tetramethylammonium chloride, tetraethyl ammoniumchloride, tetrapropylammonium chloride, tetrabutylammonium chloride,methyltriethylammonium chloride, ammonium fluoride, tetramethylammoniumfluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride,tetrabutylammonium fluoride, methyltriethylammonium fluoride, or acombination thereof.

Aspect 9. The method defined in any one of the preceding aspects,wherein impregnating the bound zeolite base with the transition metalprecursor, chlorine precursor, and fluorine precursor comprises mixingthe bound zeolite base with an aqueous solution comprising thetransition metal precursor, the chlorine precursor, and/or the fluorineprecursor.

Aspect 10. A supported catalyst obtained by the method defined in anyone of the preceding aspects, e.g., a supported aromatization catalyst.

Aspect 11. A supported catalyst comprising:

a bound zeolite base;

from about 0.3 wt. % to about 3 wt. % of a transition metal;

from about 1.8 wt. % to about 4 wt. % of chlorine; and

from about 0.4 wt. % to about 1.5 wt. % of fluorine; based on the totalweight of the supported catalyst; and wherein

the supported catalyst is characterized by a peak reduction temperatureon a Temperature Programmed Reduction curve in a range from about 580°F. to about 800° F.

Aspect 12. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst comprises any weight percentageof chlorine disclosed herein, e.g., from about 2 wt. % to about 3.8 wt.%, from about 2.2 wt. % to about 3.6 wt. %, from about 2.2 wt. % toabout 3.4 wt. %, or from about 2.5 wt. % to about 3.3 wt. % chlorine.

Aspect 13. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst comprises any weight percentageof fluorine disclosed herein, e.g., from about 0.5 wt. % to about 1.3wt. %, from about 0.5 wt. % to about 1.1 wt. %, or from about 0.6 wt. %to about 0.9 wt. % fluorine.

Aspect 14. The catalyst or method defined in any one of the precedingaspects, wherein the bound zeolite base (or the supported catalyst)comprises a zeolite and a binder.

Aspect 15. The catalyst or method defined in aspect 14, wherein thebound zeolite base (or the supported catalyst) comprises any weightpercentage of binder disclosed herein, e.g., from about 3 wt. % to about35 wt. %, or from about 5 wt. % to about 30 wt. % binder, based on thetotal weight of the bound zeolite base (or the supported catalyst).

Aspect 16. The catalyst or method defined in aspect 14 or 15, whereinthe binder comprises an inorganic solid oxide, a clay, or a combinationthereof.

Aspect 17. The catalyst or method defined in aspect 14 or 15, whereinthe binder comprises alumina, silica, magnesia, boria, titania,zirconia, a mixed oxide thereof, or a mixture thereof.

Aspect 18. The catalyst or method defined in aspect 14 or 15, whereinthe binder comprises silica.

Aspect 19. The catalyst or method defined in any one of the precedingaspects, wherein the bound zeolite base (or the supported catalyst)comprises a bound L-zeolite.

Aspect 20. The catalyst or method defined in any one of aspects 1-18,wherein the bound zeolite base (or the supported catalyst) comprises abound barium ion-exchanged L-zeolite.

Aspect 21. The catalyst or method defined in any one of aspects 1-18,wherein the bound zeolite base (or the supported catalyst) comprises abound K/L-zeolite.

Aspect 22. The catalyst or method defined in any one of aspects 1-17,wherein the bound zeolite base (or the supported catalyst) comprises asilica-bound K/L-zeolite

Aspect 23. The catalyst or method defined in aspect 22, wherein thebound zeolite base is produced by a process comprising:

combining a K/L-zeolite with a silica sol to form a mixture, extrudingthe mixture to form an extrudate,

drying, and calcining the extrudate to form a calcined base; and

washing, drying, and calcining the calcined base to form the boundzeolite base.

Aspect 24. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst comprises any weight percentageof transition metal disclosed herein, e.g., from about 0.5 wt. % toabout 2.5 wt. %, from about 0.5 wt. % to about 2 wt. %, or from about0.7 wt. % to about 1.5 wt. % transition metal.

Aspect 25. The catalyst or method defined in any one of the precedingaspects, wherein the transition metal comprises platinum.

Aspect 26. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst comprises any weight percentageof platinum disclosed herein, e.g., from about 0.5 wt. % to about 2.5wt. %, from about 0.5 wt. % to about 2 wt. %, or from about 0.7 wt. % toabout 1.5 wt. % platinum.

Aspect 27. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a peaktemperature on a TPR curve in any range disclosed herein, e.g., fromabout 580° F. to about 750° F., from about 600° F. to about 730° F., orfrom about 600° F. to about 720° F.

Aspect 28. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a TPR curvecomprising a lower temperature peak and a higher temperature peak, andwherein the higher temperature peak is greater in height than the lowertemperature peak.

Aspect 29. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst comprises any weight ratio ofchlorine:fluorine disclosed herein, e.g., from about 1.5:1 to about 8:1,from about 2:1 to about 5:1, or from about 3:1 to about 4.5:1.

Aspect 30. The catalyst or method defined in any one of aspects 6-31,wherein the reduced (or activated) supported catalyst comprises anyweight percentage of chlorine disclosed herein, e.g., from about 0.2 wt.% to about 1.3 wt. %, from about 0.2 wt. % to about 0.8 wt. %, or fromabout 0.3 wt. % to about 1 wt. % chlorine, based on the total weight ofthe reduced (or activated) supported catalyst.

Aspect 31. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst has a platinum dispersion thatis substantially the same as that of a catalyst having from 0.3 wt. % to1.5 wt. % chlorine, under the same catalyst preparation conditions.

Aspect 32. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst has a surface area that issubstantially the same as that of a catalyst having from 0.3 wt. % to1.5 wt. % chlorine, under the same catalyst preparation conditions.

Aspect 33. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst has a total nitrogen contentthat is greater than that of a catalyst having from 0.3 wt. % to 1.5 wt.% chlorine, under the same catalyst preparation conditions (by anyamount disclosed herein, e.g., at least about 50% greater, at leastabout 100% greater, or at least about 200% greater).

Aspect 34. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a T_(EOR)(end of run temperature) in any range disclosed herein, e.g., from about920° F. to about 940° F., or from about 920° F. to about 930° F.

Aspect 35. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a T_(EOR)less than that of a catalyst having from 0.3 wt. % to 1.5 wt. %chlorine, under the same catalyst preparation and aromatization reactionconditions.

Aspect 36. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a T_(SOR)(start of run temperature) in any range disclosed herein, e.g., fromabout 915° F. to about 935° F., or from about 915° F. to about 930° F.

Aspect 37. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a T_(SOR)less than that of a catalyst having from 0.3 wt. % to 1.5 wt. %chlorine, under the same catalyst preparation and aromatization reactionconditions.

Aspect 38. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a FoulingRate in any range disclosed herein, e.g., less than about 0.12° F./min,or less than about 0.1° F./min.

Aspect 39. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by a FoulingRate less than that of a catalyst having from 0.3 wt. % to 1.5 wt. %chlorine, under the same catalyst preparation and aromatization reactionconditions.

Aspect 40. The catalyst or method defined in any one of the precedingaspects, wherein the supported catalyst is characterized by an aromaticsselectivity (or a benzene+toluene selectivity) that is substantially thesame as that of a catalyst having from 0.3 wt. % to 1.5 wt. % chlorine,under the same catalyst preparation and aromatization reactionconditions.

Aspect 41. A reforming process comprising contacting a hydrocarbon feedwith a supported aromatization catalyst under reforming conditions in areactor system to produce an aromatic product, wherein the supportedaromatization catalyst is the supported catalyst (or the reduced oractivated catalyst) defined in any one of the preceding aspects.

Aspect 42. The process defined in aspect 41, wherein the hydrocarbonfeed is any hydrocarbon feed disclosed herein, e.g., comprisingnon-aromatic hydrocarbons, comprising C₆-C₉ alkanes and/or cycloalkanes,or comprising C₆-C₈ alkanes and/or cycloalkanes.

I claim:
 1. A method of producing a supported catalyst, the methodcomprising: (a) impregnating a bound zeolite base with a transitionmetal precursor, a chlorine precursor, and a fluorine precursor to forman impregnated zeolite base, wherein the bound zeolite base comprises abinder and a large pore zeolite having an average pore diameter in arange of from about 7 Å to about 12 Å; and (b) drying and then calciningthe impregnated zeolite base to produce the supported catalyst; whereinthe supported catalyst comprises, based on the total weight of thesupported catalyst: from about 0.3 wt. % to about 3 wt. % of atransition metal, wherein the transition metal comprises a Group 8-11transition metal; from about 1.8 wt. % to about 4 wt. % of chlorine; andfrom about 0.4 wt. % to about 1.5 wt. % of fluorine; and wherein thesupported catalyst is characterized by a peak reduction temperature on aTemperature Programmed Reduction curve in a range from about 580° F. toabout 800° F.
 2. The method of claim 1, wherein impregnating the boundzeolite base with the transition metal precursor, the chlorineprecursor, and the fluorine precursor comprises mixing the bound zeolitebase with an aqueous solution comprising the transition metal precursor,the chlorine precursor, and the fluorine precursor.
 3. The method ofclaim 1, wherein the method further comprises a reducing step after thedrying and calcining of the impregnated zeolite base, the reducing stepcomprising contacting the supported catalyst with a reducing gas streamto produce an activated catalyst.
 4. The method of claim 3, wherein theactivated catalyst comprises from about 0.2 wt. % to about 1.3 wt. % ofchlorine, based on the total weight of the activated catalyst.
 5. Themethod of claim 1, further comprising: combining the large pore zeolitewith the binder to form a mixture, and extruding the mixture to form anextrudate; drying and calcining the extrudate to form a calcined base;and washing, drying, and calcining the calcined base to form the boundzeolite base.
 6. The method of claim 1, wherein drying the impregnatedzeolite base comprises drying at a temperature in a range from about 50°C. to about 200° C. at atmospheric pressure or a sub-atmosphericpressure.
 7. The method of claim 1, wherein calcining the impregnatedzeolite base comprises calcining at a peak calcining temperature in arange from about 200° C. to about 500° C. in a calcining gas streamcomprising nitrogen, oxygen, air, or any combination thereof.
 8. Themethod of claim 1, wherein impregnating the bound zeolite base with thetransition metal precursor comprises mixing the bound zeolite base withthe transition metal precursor, wherein the transition metal precursorcomprises tetraamineplatinum(II) chloride, tetraamineplatinum(II)nitrate, platinum(II) acetylacetonate, platinum(II) chloride, ammoniumtetrachloroplatinate(II), chloroplatinic acid, platinum (II) nitrate, ora combination thereof.
 9. The method of claim 1, wherein impregnatingthe bound zeolite base with the chlorine precursor and the fluorineprecursor comprises mixing the bound zeolite base with the chlorineprecursor and the fluorine precursor, wherein: the chlorine precursorcomprises ammonium chloride, tetramethylammonium chloride,tetraethylammonium chloride, tetrapropylammonium chloride,tetrabutylammonium chloride, methyltriethylammonium chloride, or acombination thereof; and the fluorine precursor comprises ammoniumfluoride, tetramethylammonium fluoride, tetraethylammonium fluoride,tetrapropylammonium fluoride, tetrabutylammonium fluoride,methyltriethylammonium fluoride, or a combination thereof.
 10. Themethod of claim 1, wherein impregnating the bound zeolite base with thetransition metal precursor, the chlorine precursor, and the fluorineprecursor comprises mixing the bound zeolite base with an aqueoussolution comprising the transition metal precursor, the chlorineprecursor, and/or the fluorine precursor.
 11. The method of claim 1,wherein the supported catalyst is characterized by a peak reductiontemperature on a Temperature Programmed Reduction curve in a range fromabout 600° F. to about 720° F.
 12. The method of claim 1, wherein: thebound zeolite base comprises from about 5 wt. % to about 30 wt. % of thebinder, based on the total weight of the bound zeolite base; the boundzeolite base comprises a silica-bound K/L-zeolite; and the transitionmetal comprises platinum.
 13. The method of claim 12, wherein: thesupported catalyst has a platinum dispersion that is substantially thesame as that of an otherwise identical catalyst having from 0.3 wt. % to1.5 wt. % chlorine, under the same catalyst preparation conditions; andthe supported catalyst has a surface area that is substantially the sameas that of an otherwise identical catalyst having from 0.3 wt. % to 1.5wt. % chlorine, under the same catalyst preparation conditions.
 14. Themethod of claim 1, wherein: the bound zeolite base comprises asilica-bound K/L-zeolite; and the supported catalyst comprises: fromabout 0.7 wt. % to about 1.5 wt. % of platinum; from about 2 wt. % toabout 3.3 wt. % of chlorine; and from about 0.5 wt. % to about 1.3 wt. %of fluorine.
 15. The method of claim 14, wherein: the supported catalystis characterized by a peak reduction temperature on a TemperatureProgrammed Reduction curve in a range from about 600° F. to about 720°F.; and/or the supported catalyst is characterized by a TemperatureProgrammed Reduction curve comprising a lower temperature peak and ahigher temperature peak, and wherein the higher temperature peak isgreater in height than the lower temperature peak.
 16. The method ofclaim 3, wherein the reducing step comprising contacting the supportedcatalyst with the reducing gas stream at a reducing temperature in arange from about 100° C. to about 700° C. to produce the activatedcatalyst, wherein the reducing gas stream comprises hydrogen.